IIB. Field of Invention
This invention relates generally to apparatus used in bird hunting and bird watching activities, and more particularly to a spray coating for decoys, camouflaged clothing and related apparatus that absorbs and inhibits reflectance of ultraviolet light.
IIC. Background and Description of Prior Art
Color is an interpretation of light waves having a particular wavelength. While it is an organism's eye that receives light waves, it is the organism's brain that interprets those light waves and “sees” colors.
A transparent lens called the cornea is at the front of the eye to allow light waves into the eye. Behind the cornea is the iris, which gives the eye its color. By changing size, the iris regulates the amount of light entering the pupil, which is the orifice defined by the iris. Located behind the iris is a crystalline lens which focuses the light rays entering the eye onto the retina. The retina is the inner most layer of the eye and is covered with photo receptor cells. Light waves enter the eye through the cornea, pass through the pupil are focused by the lens and strike the photo receptors on the retina.
There are two types of photo receptors, rods and cones, which are named for their relative shapes. Rod type photo receptors perceive the intensity of light and enable an organism to see at night. Cone type photo receptors perceive the wavelengths of various light waves and enable the organism to distinguish colors.
Humans are among the minority of mammals that have color vision. In the human eye, rods are found at the peripheral regions of the retina but are nearly absent from the center of the visual field, known as the fovea, where the cones are concentrated. The human eye has about 150,000 cones (color receptors) per square millimeter of fovea area. Humans' eyes have three variants of photo-receptive cones (known as red cones, blue cones and green cones) and for that reason humans are classified as trichromic organisms. Each variant of photo receptive cone carries a unique protein, called an opsin, that reacts when struck by light waves having wavelengths that correspond to the opsin's light sensitivity. It is unknown whether the reaction is physical, chemical or both. The reaction of the opsin is communicated to the brain allowing the organism to distinguish between red, blue and green colors. Thus, the world visually perceived by humans is dominated by light having wave lengths ranging from 400-750 nanometers, or blue to red respectively.
In contrast to humans, birds have tetra-chromic vision. The eyes of tetra-chromic organisms have four variants of photo receptive cones. In addition to having three variants of cones with opsins sensitive to red, green and blue light, birds have a fourth variant of cone with an opsin that is sensitive to ultra violet (UV) light which presumptively enables the organism to perceive ultra violet light that is invisible to humans. The peak sensitivity of the opsin on this fourth variant of photo receptive cone is at about 358 nanometers which is known as Ultra Violet A (UVA) light.
As noted above, while a human eye has about 150,000 cones per square millimeter of fovea area, the eyes of birds have more than one million cones per square millimeter of fovea area. This large difference in the number of cone type photo receptors presumptively provides birds with greater visual acuity than humans, as well as an ability to perceive UV light that is invisible to humans.
Because perceived color is likely dependent upon the number and types of photo receptors in the eye, theoretically birds not only perceive UV colors that are invisible to humans, it is also likely birds perceive the human visible spectrum differently. While the fourth type of photo receptive cone presumptively increases the range of wave lengths birds can perceive, likely creating a quantitative difference in visual ability, the increased dimensionality also likely produces a qualitative change that cannot be translated into human experience. Most likely, “bird colors” are not simply refinements of human hues, but rather it is more likely that “bird colors” are unknown to tri-chromic organisms and thus cannot be described in human terms.
The inability to know what colors and hues are perceived by birds has dramatic implications for the manufacture, construction, design, and use of outdoor sporting apparatus such as decoys, blinds, camouflaged clothing and the like. Items manufactured for use in bird hunting and bird watching activities contain synthetic materials and dyes that may interact with UV light waves differently than similar appearing organic materials. The result may be a decoy, blind or camouflaged clothing that, from the perspective of a human, looks identical to the natural object, but is perceived by a bird to be radically unnatural.
It has been observed that waterfowl and other game birds will unhesitently land in a grouping of decoys during morning and evening twilight, but will avoid the same grouping of decoys during hours of daylight. Coincidentally, UV light is nearly absent during the hours of twilight when the sun's rays are refracted through the earth's atmosphere but are prevalent during the hours of daylight.
It is impractical, if not impossible to precisely duplicate the natural reflectance of UV light off the feathers of birds because the reflectance and color hues are in the UV range that humans cannot perceive. Without being able to perceive the reflectance, any attempt of realistically mimicking the reflection is guesswork. The solution to this problem is to diminish the reflectance of ultraviolet light while maintaining a presumptively natural appearance in the visual spectrum.
The instant invention is a spray on, quick drying, water resistant composition that enhances the effectiveness of decoys, blinds, camouflaged clothing and related apparatus used in bird hunting and bird watching activities. The composition presumptively functions by various methodologies including absorbing UV light waves, converting UV light waves into heat energy and possibly reflecting UV light waves at altered wave lengths not in the UV spectrum although the precise nature of how the composition operates is unknown.